A seatbelt generally comprises belt webbing that passes over a vehicle occupant's torso to restrain forward movement in a crash. The webbing is wound on a spool that is mounted in the retractor for rotation about its longitudinal axis to wind in or pay out webbing. The spool is biased in a winding in direction by a spiral spring. A sensor detects a crash, for example by detecting acceleration or deceleration above a predetermined level. The crash sensor activates a locking mechanism to lock the spool against rotation and prevent further pay out of webbing thus restraining the occupant against forward motion.
The spool is locked by engagement of teeth on a ratchet wheel on the edge of the spool with a locking pawl. Often two locking pawls are used mounted at opposite ends of a bar extending the length of the spool so as to lock both ends simultaneously. Such a lockbar is traditionally made in one piece of a single type of material, for example as a metal die casting.
However, die cast parts are inherently rather weak and the traditional U-shaped lockbar is complex to manufacture.
The present invention provides an improved lockbar for a seatbelt retractor and an improved method of manufacturing or assembling a lockbar.